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NOTES Endocrine System
1
Endocrine System
Roles of the Endocrine System
• glands that produce chemicals (hormones) released into the blood
• General role:> Maintain homeostasis> Regulate growth and development> Coordinate energy use
Regulate response to stim
NOTES Endocrine System
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Types of Hormones• 1. Amines: Examples: epineprine and thyroid hormones
• 2. Prostaglandins: act as chemical messengers, but do not move to other sites
• 3. Steroid hormones: Examples: testosterone and estrogen
• 4. Peptide and Protein hormones: are the largest and most complex hormones. Example: insulin.
Glands and Hormones
NOTES Endocrine System
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Hormones• found in plants as well• In humans: maintain conditions in the body
> Temperature> pH> Water balance> Growth > Development • The hormone travels to a specific
site: the target cells have receptors on them for this purpose
• Hypothalamus Gland:> lower central part of the brain> regulation of satiety, metabolism, and body temperature > secretes hormones that control the pituitary gland.
> Ex somatostatincauses the pituitary gland to stop the release of growth hormone.
NOTES Endocrine System
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• Pituitary Gland:• base of the brain, no larger than a pea • control many functions of other endocrine glands
> The anterior lobe – Growth hormone – Thyroidstimulating hormone (TSH) – Adrenocorticotropin hormone (ACTH) – Luteinizing hormone (LH) and folliclestimulating hormone (FSH) control
sexual function and production of the sex hormones– Prolactin stimulates milk production in females
> The posterior lobe– Antidiuretic hormone Controls water loss by the kidneys– Oxytocin Contracts the uterus
• Pineal Gland:> middle of the brain > Melatonin: regulate the wakesleep cycle
NOTES Endocrine System
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• Thyroid Gland:> lower front part of the neck> thyroid hormones: regulate metabolism > bone growth and development of the brain and nervous system in
children > maintain normal blood pressure, heart rate, digestion, muscle tone,
and reproductive functions
• Parathyroid Gland:> 2 pairs of small glands embedded in the surface of the thyroid gland> parathyroid hormone: regulating calcium levels
• Adrenal Glands:> located on top of each kidney
« corticosteroids» regulate the body’s metabolism, the balance of
salt and water in the body, the immune system, and sexual function
« produces hormones (eg, adrenaline)» help the body cope with physical and emotional
stress by increasing the heart rate and blood pressure.
NOTES Endocrine System
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• Pancreas:
> toward the back of the abdomen behind the stomach> digestive and hormonal functions > digestive enzymes > secretes hormones
– insulin and glucagonregulate the level of glucose (sugar) in the blood
Comparing Control Systems
NOTES Endocrine System
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Feedback LoopsNegative feedback
Causes activity to turn off until the right level is reached (detects too much of something) [hormone regulation]
Positive feedbackCauses an increase in activity until the right level is reached (detects too little of something) [contractions during child birth/blood clotting]